The Information Age is upon us. Access to vast quantities of information through a variety of different communication systems are changing the way people work, entertain themselves, and communicate with each other.
For example, because of the 1996 Telecommunications Reform Act, traditional cable television program providers have now evolved into full-service providers of advanced video, voice and data services for homes and businesses. A number of competing cable companies now offer cable systems that deliver all of the just-described services via a single broadband network.
These services have increased the need for bandwidth, which is the amount of data transmitted or received per unit time. More bandwidth has become increasingly important, as the size of data transmissions has continually grown. Applications such as in-home movies-on-demand and video teleconferencing demand high data transmission rates. Another example is interactive video in homes and offices.
Other industries are also placing bandwidth demands on Internet service providers, and other data providers. For example, hospitals transmit images of X-rays and CAT scans to remotely located physicians. Such transmissions require significant bandwidth to transmit the large data files in a reasonable amount of time. These large data files, as well as the large data files that provide real-time home video are simply too large to be feasibly transmitted without an increase in system bandwidth. The need for more bandwidth is evidenced by user complaints of slow Internet access and dropped data links that are symptomatic of network overload.
In addition, the wireless device industry has recently seen unprecedented growth. With the growth of this industry, communication between different wireless devices has become increasingly important. Conventional radio frequency (RF) technology has been the predominant technology for wireless device communication for decades.
Conventional RF technology employs continuous carrier sine waves that are transmitted with data embedded in the modulation of the sine waves' amplitude or frequency. For example, a conventional cellular phone must operate at a particular frequency band of a particular width in the total frequency spectrum. Specifically, in the United States, the Federal Communications Commission (FCC) has allocated cellular phone communications in the 800 to 900 MHz band. Generally, cellular phone operators divide the allocated band into 25 MHz portions, with selected portions transmitting cellular phone signals, and other portions receiving cellular phone signals.
Another type of inter-device communication technology is ultra-wideband (UWB). One type of UWB wireless technology employs discrete pulses of electromagnetic energy and is fundamentally different from conventional carrier wave RF technology. UWB can employ a “carrier free” architecture, which does not require the use of high frequency carrier generation hardware, carrier modulation hardware, frequency and phase discrimination hardware or other devices employed in conventional frequency domain communication systems.
One feature of this type of UWB is that a UWB signal, or pulse, may occupy a very large amount of RF spectrum, for example, generally in the order of Giga-Hertz of frequency band. Currently, the FCC has allocated the RF spectrum located between 3.1 Giga-Hertz and 10.6 Giga-Hertz for UWB communications. The FCC has also mandated that UWB signals, or pulses must occupy a minimum of 500 Mega-Hertz of RF spectrum.
Developers of UWB communication devices have proposed different architectures, or communication methods for ultra-wideband devices. In one approach, the available RF spectrum is partitioned into discrete frequency bands. A UWB device may then transmit signals within one or more of these discrete sub-bands. Alternatively, a UWB communication device may occupy all, or substantially all, of the RF spectrum allocated for UWB communications.
UWB is one form of wireless communications technology that requires extremely large bandwidth. Reliable transmission and reception of wireless UWB signals therefore requires antennas that can radiate and receive across a very wide band of frequencies. With the development of UWB communications, and the continual deployment of new devices that use larger bandwidth carrier wave technology, a need exists for a reliable antenna that can transmit and receive communication signals over a very wide band of radio frequencies.